Migrant arrivals in Germany dropped significantly last month, but the reason was rough seas, not efforts by Turkey to crack down on illegal departures to Greece, German Interior Minister Thomas de Maiziere said on Wednesday.
His remarks suggest that German efforts to stem the flow of arrivals with help from Turkey are not effective yet, which increases pressure on Chancellor Angela Merkel, whose popularity has fallen over her decision to welcome refugees.
"Our impression is that the drop (in arrivals) is predominantly linked to the weather, namely a stormy sea in the Mediterranean," de Maiziere, a member of Merkel's Christian Democratic Union (CDU), told a news conference.
"We are also seeing efforts by Turkey to reduce the number of illegal migration departure from Turkey," he said. "But we cannot confirm a sustainable, permanent, and visible reduction because of these activities and based on individual steps in December."
From 2,500 to 4,000 migrants entered Germany through Austria each day in December. That is far less than 10,000 daily arrivals recorded at the height of the crisis in autumn but still not low enough to silence Merkel's critics.
Most migrants reach Europe by making the short voyage from Turkey to Greece. Merkel wants Turkey to stem the flow and take back asylum seekers rejected by Europe.
In exchange, Turkey will get support for faster action on its bid to join the European Union and billions of euros in aid for Syrian refugees in border camps.
The chancellor has rejected demands from members of her own conservatives to cap the number of refugees Germany is willing to take each year as well as calls to seal the border with Austria.
Her multi-front approach to reducing the number of arrivals also includes providing aid to Syrian refugees in Lebanon and Jordan and distributing asylum seekers across the European Union.
Merkel's CDU and its sister party, Bavaria's Christian Social Union (CSU), have been rising in opinion polls since November, when the number of daily arrivals began to drop.
Support for the CDU-CSU has stood at 38 to 39 percent over the last three weeks, up from 36 percent at the height of the crisis but still below the 41.5 percent of they vote they won in the 2013 election.
Germany registered 1.09 million asylum seekers in 2015, five times more than a year earlier, sources in the coalition government, which included the left-leaning Social Democrats, told Reuters on Wednesday, confirming local media reports.
Merkel will find it even more difficult to defend her refugee policy if a similar number is recorded this year.
The huge influx has forced authorities to register migrants upon entering Germany and have them wait in temporary accommodation centers before they can officially file asylum applications.
Just over 476,000 migrants applied for asylum last year, the highest number ever recorded in Germany, the Interior Ministry said. That number will rise when the asylum applications of the remaining 600,000 registered migrants are collected.
The last record was set in 1992 when 438,000 asylum applications were filed by people fleeing conflicts in the former Yugoslavia.
Syrians made up the largest share of the more than one million migrants who entered Germany last year, accounting for 40 percent of the total, the ministry said in a statement.
So far, German authorities have approved 48.5 percent of the 282,700 asylum applications processed in 2015.